Inside Fugate's tuning room, the tubes rest on braces. He strikes them with a hammer and then listens while adjusting a mechanical tuner, an instrument that emits light to match the frequency of the note. Mark Guarino3 / 3

MORTON, Ill. - Two hours after dawn breaks, Brett Fugate waits to catch the early-morning wind as it moves across the soybean fields that border his one-story welding shop.

He is outside, atop a makeshift tower, one arm balancing his body on a railing, the other holding a large steel chime. The wind is coming, and once it does, he'll get a better sense of how the chime will toll, not just across the rural flatlands of central Illinois, but in September in a Pennsylvania field when it, along with 39 others, will ring in perpetuity for the 40 people who died there Sept. 11, 2001.

The chimes represent the key component of the nearly 100-foot-tall Tower of Voices, the final installation of the Flight 93 National Memorial, a 2,200-acre park located on a former reclaimed strip mine in Somerset County, Pa. It is where United Airlines Flight 93, bound for San Francisco from Newark, N.J., crashed, killing everyone on board. Hijackers had intended to direct the Boeing 757 to Washington, D.C., but the 40 passengers and crew members carried out an insurrection that prevented further catastrophe, the kind that happened that day at the World Trade Center in New York and at the Pentagon.

More than 600 miles away, Fugate dashes around in his workshop just days before the chimes will be shipped to their permanent home for a Sept. 9 unveiling. Since December, he and five employees have quietly sourced, carried, cut and tuned the chimes, each one representing people he did not know but is likely to never forget.

"It changed my life. It's an honor to be part of it," Fugate said of the project. "But I wish 9/11 never happened."

A journey

The Tower of Voices represents the final phase of the memorial that the National Park Service first commissioned in 2005. In an international competition, a jury made up of architects, family members and others chose Paul Murdoch Architects, a Los Angeles-based firm that created a plan to treat the entire landscape as a living memorial, rather than installing a traditional structure that did not change over time.

Murdoch and his team envisioned a series of sequences connected to the natural environment that told the story of the passengers and crew. The bowl shape of the site is used to lead visitors along an edge of 40 red maple trees that end with a plaza that features the names of the passengers and crew members, cast in white marble. There is an incompleteness to the journey, as the circle opens to the crash site itself, which was once a crime scene and is now a place that has been given over to nature.

The design takes visitors on a nearly mile-long walk around the area of the flight path to the crash site, rather than creating a direct funnel. The choice forces contemplation, to put visitors in a different state of mind from the one they were in the moment they stepped out of their cars. As they travel along the walkway, the insignificant details of their day are shed. By the time the walk ends, they are confronted with both the horror and heroic actions of that day.

Murdoch, who grew up in Newtown Square, Pa., says that incorporating the power of the landscape—the vista of trees, the expanse of the field, the quiet beauty of the Pennsylvania countryside—is what makes the memorial different than traditionally designed memory spaces.

"This is the place where it happened. It wasn't on the Mall. We felt like we didn't have to re-create certain things. All we had to do was work with what was there," he says.

The vertical counterpoint to the memorial is the Tower of Voices. Standing at a symbolic 93 feet, the tower will be high enough to allow visitors to walk underneath once they enter the site. Sound became a part of Murdoch's design for different reasons: Flight 93 passengers used their cellphones to call loved ones to say goodbye, and the randomness of those voices—like the random events that put those passengers and crew members together that morning—are now memorialized together in a united place.

"We wanted a dialogue between the site and what happened on that plane," he says. "So the sound changing in the wind seemed to be an aspect of what the chimes could offer, as well as behaving as an entire group of 40 people. That it would change every moment, every day, year after year seemed suitable."

What the full set of chimes will sound like won't be known until they are installed this month. Weather, temperature and winds of up to 150 miles per hour are all factors that will affect the sound, and because they are different sizes to accommodate a five-octave scale, not all the chimes are expected to ring at one time. They will serve "as the welcoming beacon" to visitors, said Stephen Clark, superintendent of the Flight 93 National Memorial. Each chime is individually tuned, which Clark says makes them the perfect representative of the people fighting for their lives on that flight.

"In essence, they were individuals, but they acted as one. That's why these voices, these chimes, this tower truly represent their courage and their spirit as a group in perpetuity," he says.

Fine tuning

A heavy-metal musician and composer in rural Illinois who is prone to quoting lyrics by Rush or KISS to make a point might seem an unlikely choice to create the memorial chimes, but Fugate is not a typical metalhead. With degrees in molecular biology and music, he has been making instruments for 25 years, a pursuit that kept him in the music business after many years fronting two metal bands based in the Chicago area.

Tuning incorporated science into musicmaking gave him entryway into an art that requires patience and a nuanced set of ears. He says he was awarded the job because he possessed two skills that most candidates did not: a background in machinery and welding, and more than 20 years as a professional instrument tuner for various instrument companies.

"The chimes have to be cut to very specific lengths to create the different pitches. Brett's experience tuning musical instruments is really critical to getting the musical part of the chime assembly tuned to the notes that we want," Murdoch says.

Fugate, 45, grew up in East Peoria and discovered a love for both prog rock and classical music at an early age. But he was drawn to unusual instruments. At a school competition in Nashville, he insisted on playing Niccolò Paganini's Violin Concerto No. 1 on the xylophone, his preferred instrument.

He also discovered he was mechanical and, besides composing songs for his metal band Idiom, he took jobs on which he developed skills tuning instruments such as xylophones and marimbas that are most prone to changes in temperature and humidity. On Sept. 11, 2001, he was at work, tuning two five-octave marimbas at a plant in Chicago, when a co-worker told him that a plane had crashed into one of the twin towers. Eventually, the entire work crew gathered around televisions in the lunchroom to watch what, it became clear, was an act of international terrorism.

The chimes for the memorial required the precision of Fugate's hand. Weighing up to 150 pounds and ranging from 8 to 16 inches in diameter and up to 10 feet in height, the aluminum tubes have internal stainless-steel strikers attached to sails projecting from their bottom. He had never tuned tubes that big, so he had to first procure tubes in 12-foot increments and move them into his shop by hand. The tuning room has a low ceiling for sound, so they were too tall for his forklift.

The next step was determining the different lengths according to the pitches and cutting 40 of them in his shop. Then came the tuning: Inside Fugate's tuning room, the tubes rest on braces. He strikes them with a hammer and then listens while adjusting a mechanical tuner, an instrument that emits light to match the frequency of the note.

"The ear is part of the process. I use the mechanical strobe (tuner), but you make judgments with the ear," he says.

The work, which started in January, meant continuous long days and doubling his staff to six people. The fruits of their labors, however, will remain a mystery until Sept. 9. "We've got an idea of what it might sound like," he says. "But nobody has heard it in full."

Anticipating the moment

For family members of the 40 passengers and crew members of Flight 93, the chimes, when they finally ring, will be more than sound meeting the sky.

"It will automatically bring back my cousin Lorraine's voice. I can hear her now, thinking about it," he says.

The total cost of the tower was $6 million, which came from private donations; $400,000 of the total came directly from families of those who died that day, Clark says.

Leading the fundraising effort was Families of Flight 93, a nonprofit group formed in 2002. "It's given me something to focus on," says Gordon Felt, the organization's president, whose older brother Edward Porter Felt died that day.

In earlier years, Felt visited the memorial and found himself listening to schoolchildren ask questions about what took place on Flight 93 and learning about the heroism of people like his brother. Now, upon returning, he'll listen to voices in the sky - "a continual sound," he says, ringing from the tower.

"I get a great sense of satisfaction knowing it will stand there forever," he says.